The present invention relates generally to continuous shot-blasting machines for surface treating arbitrary arrangements of batches of workpieces which are carried on a conveyor device and, more particularly, to such shot-blasting machines which includes means for turning or rotating the workpieces so that all surfaces can be exposed to the shot-blasting treatment.
Shot-blasting machines which include devices or means for turning the workpieces over or causing them to otherwise rotate in order to expose all surfaces of the workpieces to proper surface treating are, of course, known in the art. One such known shot-blasting machine is shown and described in British Patent Specification No. 778,848 in which the workpieces to be treated are carried in batches on a revolving conveyor belt and are circulated or turned over for surface treatment of all sides of the workpieces by the up and down movement of rollers in a trough which carry the workpieces. After the blasting operation, the workpieces are conveyed to a delivery station by lowering the rollers which operate in the trough to the level of a horizontal conveyor belt for transporting the workpieces.
This type of shot-blasting machine is particularly suited for surface treating workpieces, all of which have the same uniform shape but is unsuitable for treating batches of workpieces with different or non-uniform shapes. A further disadvantage of this type of shot-blasting machine is that the turning of the various workpieces occurs irregularly so there is no way to insure that each workpiece will be turned by the same amount for receiving the same surface treatment on all sides.
Another type of blasting machine using a device for turning the workpieces is shown in U.S. Pat. No. 2,565,341 which includes a drum shaped cage for carrying the workpieces to be treated. The cage is arranged on rails for rotatable movement through a sand-blasting chamber. During the rotatable movement the workpieces are caused to circulate or otherwise tumble within the cage. This type of device also suffers from the disadvantages mentioned above and further has a limited capacity since a new batch of workpieces can only be treated when a preceeding batch has been removed from the cage.
It is accordingly one object of the present invention to provide a shot-blasting machine having means for rotating the workpieces to be treated which overcomes the disadvantages of the prior art.
It is a further more specific object of the present invention to provide a shot-blasting machine for the continuous treating of arbitrarily arranged workpieces having a means for turning over each workpiece regardless of its shape so that each of its surfaces is exposed for uniform treatment.
Yet another object of the present invention is to provide a shot-blasting machine of the foregoing type which can be continuously operated rendering it capable of being integrated into a plant or system for automatically molding and casting workpieces.
Still another object of the present invention is to provide a shot-blasting machine which uniformly treats all of the surfaces of arbitrarily arranged workpieces regardless of their shape or configuration.
Other objects, features, and advantages of the present invention will become more apparent from the detailed description of the invention in connection with the drawings to be described more fully hereinafter.